As it is known, a solid state memory, for example an Integrated Circuit (IC) Card, a Subscriber Identification Module (SIM) or a Universal Serial Bus (USB) memory, comprises a microprocessor and is suitable for storing digital contents that can be read by an external device, for example by a cell phone, by a multimedia reader or by a personal computer. In particular, it is possible to protect the digital contents of the memory via software of the device, that is provided to set a protection password for the data and to enable their access only after a verification of the password. For example, the programs Winzip™ or Word™ allow the protection of the digital contents with a password.
Similarly, it is known to protect the digital contents with a program of cryptography of the device, that saves the data in memory in cryptographic format and allows their reading only via a de-cryptography key. However, it is not possible to access the digital contents of the memory when it is transferred to an external device devoid of the software of cryptography, also knowing the protection password or the cryptography key.
Moreover, some reading devices of the solid state memory have a limited input interface and do not allow the input of a protection password; for example, an mp3 reader is provided with a cursor for the selection of the music pieces, for their activation, interruption or end but it is not provided with an alphanumeric keyboard for the insertion of a password.
Finally, even if in the cryptographic format, the digital contents can be copied by the solid state memory onto another storage device, and attempts made to identify the de-cryptography key and reach the content of the digital contents for free.
There is a need to protect a solid state memory that is integrated in the memory device, i.e. able to protect its digital content independently from the device reader connected thereto, i.e. independently from the software or from the interface the device is provided with, and prevent copying or reading of the digital contents in plain or cryptographic format.